1. Field of the Invention
The present invention pertains to several embodiments of a modular, multiphase fluid flowmeter system and related methods for measuring multiphase fluid flow, particularly mixtures of gas, oil and water.
2. Background
My U.S. Pat. Nos. 4,852,395, issued Aug. 1, 1989, and 5,224,372, issued Jul. 6, 1993, pertain to multiphase fluid flowmeters for measuring mixtures of gas, oil and water with a high degree of accuracy. In certain flowmeter applications, such as in low-volume oil production wells and other flow measuring requirements, the degree of accuracy required is not as great as that provided for by the meters described in the patents. 0n the other hand, there are applications for fluid flowmeters which may have a predetermined measurement accuracy requirement which changes during the life of the system to which the flowmeter is connected. Accordingly, it would be desirable in such applications to have a modular flowmeter system to which additional components could be added or deleted as the measurement accuracy requirements change or as the composition of the multiphase fluid flow being measured changes. An example of the latter requirement would be measuring flow from oil production wells wherein the water fraction or "water cut" in the liquid flowstream changes as the oil reservoir is depleted, or the amount of gas being produced with the liquid also changes as the characteristics of the oil reservoir change.
In all events, it has been deemed desirable to provide improvements in multiphase fluid flowmeters and the associated methods for measuring flow which are operable to provide continual monitoring of production of mixtures of oil, water and gas from a well wherein the metering accuracy is in a range of .+-.15% of true fluid volumes, or somewhat better than these accuracies, and wherein the cost of the metering equipment is of some importance, such as wherein the flowmeters are required to be connected to each well in a large and dispersed oilfield, for example. It is to these ends that the present invention has been developed.